Copenhagen, Denmark
The demonstration of the heat booster substation in Havnehuset, Copenhagen was part of the EnergyLab Nordhavn project.
The heat booster substation is a heat pump integrated at building level that boosts the temperature of the ultra-low temperature district heating (at forward temperatures of 35 °C to 40 °C) to temperatures high enough to provide domestic hot water. To do so the district heating stream is split. One part is used as heat source, while the other part is heated up to provide domestic hot water in a heat exchanger. The domestic hot water is produced at 55 °C and distributed to the apartments in the buildings. A buffer tank of two times 750 liter is included in the system, which ensures a high comfort level and provides flexibility regarding when to operate the heat pump. Thereby, the load on the district heating grid and on the electricity grid may be shifted to off-peak periods.
A second heat pump was included in the system to reheat the circulated domestic hot water from 50 °C to 55 °C. The demonstration project aimed at demonstrating the operation of the Heat Booster Substation as an enabling technology for ultra-low temperature district heating. Further, the potential to shift the load and thereby utilize the flexibility in the domestic hot water system to minimize operational cost was demonstrated.